not trying to tell you how to spend your time or money, but i think this is a waste of both. find a legit source and stick with them. but if you're dead set on this i would pm one of the mods who initiated the gh testing. i'm sure they can point you in the right direction.
imo go to directlabs.com and have a blood test done while on and before. Test and free test labs only run 79.00.
Testing for an unknown is more expensive. To test a solution to see whether an ingredient is present isnt too difficult but to test its strength can run into a lot of money.